HOUSE AND GARDEN 
298 
November, 
Di3 
be sounded against those forms of tar which are hard and brittle 
at ordinary temperatures and have to be melted to be applied. 
Such are sure to chip off and be unsatisfactory. 
Coal tar is the material intended wherever the word tar is 
used here. In buying tar for that purpose the only safe way is 
to get it from, or trace it from, a gas works producing gas from 
coal. In case of doubt have the dealer sign a guarantee that the 
tar is wholly the product of the destructive distillation of bitu¬ 
minous coal. 
Tar makes a very good dressing if it is carefully ap¬ 
plied and if not too much is asked of it. It is at its 
best when heavy applications are 
made in winter, when it usually 
needs to be heated, to dry and 
not too large surfaces. It is ab¬ 
sorbed by a transverse cut and is 
then to a certain extent subject to 
the drawbacks attendant on the use 
of such materials as creosote. It 
does not adhere well to moist sur¬ 
faces, blistering up easily. On 
large wounds it must be frequently 
renewed. For instance, the writer 
once had to treat a large wound 
in an ironwood tree. The exposed 
wood was dry and sound, though 
rather deeply cracked. He applied 
at intervals of a week or two, dur¬ 
ing the summer, four thorough 
coats of tar. The conditions were 
ideal for a perfect job. Four 
years later there were numerous 
holes through the tar where insects 
had escaped and there were even 
cracks through which the wood 
was visible. This does not prove 
that tar is not a valuable dress¬ 
ing. It only shows that in this 
case four years was too long to wait before re¬ 
newing the protective covering. That is the great 
point about the use of tar. It must be renewed 
at frequent intervals. How long those inter¬ 
vals can be depends upon circumstances. If a 
thorough second coat is given rapidly-healing 
pruning wounds up to, say, six inches in di¬ 
ameter, a year after the first coat, they can usu¬ 
ally be left to heal without further attention. 
Larger wounds should receive a second coat the 
year after the first one and every second year there¬ 
after, until checking absolutely ceases and a heavy 
impervious layer of tar is formed over the whole 
surface. 
For the little odds and ends—petty injuries and 
quickly-healing wounds—a thorough daub of tar is 
quite sufficient. But the strong color and staining 
quality of tar must not be permitted to lead to careless work 
with it. It must be flowed on with a full brush, and every par¬ 
ticle of the surface must be covered. 
The solid forms of asphalt can be used just as they come, being 
melted for use. There are serious difficulties, however, about ap¬ 
plying hot preparations to tree wounds, particularly if the wounds 
are high up in a tree. Most forms which need melting, also, dry 
too brittle to be perfectly effective. To avoid these drawbacks, 
the asphalt is usually fluxed with some liquid in which it will dis¬ 
solve, just enough of the solvent being used to bring the mixture 
to the proper consistency. Many substances are used for this 
purpose, including gasoline, petroleum oils of various consisten¬ 
cies, linseed oil, and other vegetable paint oils. The mixture can 
be bought ready made or can be mde by the user. 
Effective as a thorough coat of asphalt paint is, cases frequently 
arise which call for something even more strong and enduring. 
The wound may be a very large one, for instance, and difficult 
of access, so that little dependence can be put upon future re¬ 
newals of the dressing. If it is an old wound there are probably 
borers beneath the surface which may be able to break through 
even a heavy coat of asphalt. To meet such a situation we have 
always the possibility of covering the wound with zinc or copper. 
There is a method, though, which secures quite as effective a 
covering as does zinc, with less ex¬ 
pense and less work. That method 
is the reinforcement of ordinary 
brushed dressings. 
A dressing is reinforced by ap¬ 
plying a fabric to the wound and 
saturating the fabric with the dress¬ 
ing. The materials available for 
the purpose are numerous, such 
as cotton batting, burlap, cheese¬ 
cloth, and canvas. By all means 
the most satisfactory, though, is 
cotton padding, a material used in 
dressmaking. It is a thin bat of 
cotton, perhaps an eighth of an inch 
thick. All department stores sell 
it, the price being about five cents 
a square yard. 
Three steps must be observed 
in applying the reinforced dressing. 
First give the wound a thorough 
coat of the dressing. It is well to 
let this dry a day or two. Then 
press the padding against the wound 
and saturate it thoroughly with the 
dressing. At this point the padding 
which extends beyond the edges of 
the wound can be trimmed off. It takes only 
a moment to trim the edges if a sharp instru¬ 
ment is used. The writer uses old safety razor 
blades. When this saturating coat has dried 
a few days the upper surface of the cotton 
padding will usually be somewhat exposed. A 
final surface dressing is necessary in order to 
protect the cotton from the weather. When the 
job is done the presence of the cotton is barely 
discoverable. 
Not all dressings fit this process. Tar is apt to 
harden at the edges and separate from the wood. 
Paint would do fairly well, though it would be very 
expensive. The asphalt compounds work best. 
The first coat on the wound can be of tar. asphalt 
being used to saturate the fabric and for the final 
dressing. 
The manufacturers of pruning paints often advertise that their 
preparations contain nothing which could be harmful to the 
tree. The writer does not consider that an important point. 
None of the materials commonly used is seriously injurious to 
the wood. Tar usually kills back the cambium an eighth or a 
quarter of an inch, but it is normally killed as far back as that by 
drying. Carbolineum often kills the cambium a little farther, but 
is innocuous if it is kept an inch or so from the edge of the wound. 
Don't choose an expensive material over a cheap one, for the 
sole reason that its analysis indicates that it contains nothing 
which could possibly injure the cambium. The cheap one may 
(Continued on page 331) 
Another instance of how a tree may be wounded. In this case an 
iron band has eaten into the tree as the latter grew 
Most of this cambium has been 
saved by prompt treatment 
